Time synchronizing mechanism



P 8, 1953 o. H. DICKE 2,651,168

TIME SYNCHRONIZING MECHANISM Filed June 29, 1949 2 Sheets-Sheet 1 INVENTOR Oscar h, Dick:

p 8, 1953 o. H. DICKE 2,651,168

TIME SYNCHRONIZING MECHANISM Filed June 29, 1949' I v 2 Sheets-Sheet 2 INVENTQR Oscar H. D/cke Z waM AGENT Patented Sept. 8, 1953 UNITED STATES PATENT OFFICE This invention relates to mechanism for synchronizing the seconds hand of a Watch or clock with the minute hand of such watch or clock without positively gear connecting the seconds hand to such minute hand.

In both escapement clocks or watches and electric clocks the minute hand (1 R. P. H.) is usually frictionally connected to the minute shaft of such clock whereas the seconds hand (1 R. P. M.) is rigidly connected to the seconds hand shaft. This is done so that the minute hand, and the hour hand R. P. H.) gear connected to each other, may be set to correct time. In this construction the seconds hand is for obvious reasons usually out of minute synchronism or chronological agreement with the minute hand.

One object of the present invention is to provide means to prevent the continuation of such non-synchronism as by the provision of resynchronizing means.

Another object of the invention is to provide re-synchronizing means which functions entirely automaticall and rather quickly after each setting of the minute and hour clock hands.

More specifically it is proposed in accordance with the present invention to frictionally connect the minute hand to a shaft of the gear train that rotates at a speed of one revolution per hour and to frictionally connect the seconds hand to a shaft of the gear train that rotates at a speed equal to, slightly faster or slower than 60 R. P. M. and to provide suitable mechanical means to bring the two hands into minute synchronism by either braking or advancing the seconds hand at the end of each minute they are in approximate chronological agreement.

Another object of the present invention resides in the provision of a large number of evenly spaced teeth on a slow running shaft and a single tooth on a hub frictionally connected to a fast running shaft so interengaged that the teeth of the slow running shaft may determine when the tooth of the fast running shaft shall start a new revolution.

Another, and more specific object of the present invention resides in the provision of a wheel provided with sixty teeth and fixedly connected to the minute hand and frictionally connected to the l R. P. H. shaft of the clock gear train and a hub having one tooth frictionall connected to a shaft of the gear train rotating 60.75 revolutions for each revolution of the 1 R. P. H. shaft in a manner to mesh said one tooth with the 60 teeth of said wheel so that upon re-synchronization the hub is braked to an extent of 4.5 degrees at the end of each revolution.

Since in accordance with the present invention both the minute hand and the seconds hand are frictionally connected to shafts of the gear train, it is proposed in accordance with such invention to employ a much higher frictional connection for the minute hand than for the seconds hand so that the minute hand may dominate the seconds hand during interlocking action between the two hands.

Another object of a modified form of the present invention proposes the employment of an eddy current drag disk as the frictional connection between the second hand and the 60.75 R. P. H. shaft.

Other objects, purposes, and characteristic features of the present invention will be apparent from the following specification when considered in the light of the accompanying drawings in which:

Fig. 1 shows conventionally one embodiment of the present invention;

Fig. 1a shows the dial of the clock shown in Fig. 1;

Fig. 2 illustrates a portion of Fig. 1 on an enlarged scale;

Fig. 2a is a sectional elevation taken on a line Za-Za of Fig. 2 as viewed in the direction of the arrows;

Fig. 3 shows a modified form of slip clutch for the seconds hand which may be applied to the structure illustrated in Fig. 1; and

Fig. 4 shows a fragmentary portion of a modified form of the invention in which the seconds indicating shaft rotates exactly sixty times as fast as the minute indicating shaft.

Structure-Referring to Fig. l of the drawings this figure'shows one form of the invention applied to a synchronous motor electric clock. It will be seen that the synchronous motor SM drives the pinion I0 through the medium of shaft 9, also that pinions I0, I2, l4, I6, I8, 20 and 22 drive respectively gears ll, I3, I5, I'I, I9, 2! and 23. Also that pinions I2, I4, I6, I8, 20 and 22 are mechanically connected to gears I I, I3, l5, [1, I9 and 2| through the medium of shafts 3|, 33, 35, 31, 39 and 4| respectively. The pinions I0, I2, I4, I6, I8, 20 and 22 have 5, 5, 9, 9, 4, 5, and 5 teeth respectively as indicated by these numbers with the suffix 1. added thereto. The gears II, I3, I5, I'I, I9, 2| and 23 have 40, 50, 50, 72, 15, 15 and 27 teeth respectively. From these gear ratios it is readily determined that if shaft 9 is rotated at 3600 R. P. M. then shafts 31 and 43 rotate respectively at R. P. H. and 1 R. P. H. (revolutions per hour). Synchronous motor SM rotates exactly 3600 R. P. M. when exactly 60 C. P. alternating current is applied thereto. If a synchronous motor that has a synchronous speed of 459 R. P. M. is used it will be connected to the shaft 3i and the pinion ii and gear it will be omitted.

The seconds hand t? and radial pin iii are socured to a hub 38 which hub is frictionally connected, as by friction arms 2330s, to the shaft 3? (see Fig. 2a). Similarly, the minute hand 52 and toothed wheel are connected to a hub id which is frictionally connected to the shaft id as conventionally shown by the friction arms Ma. The first mentioned frictional connection 38 is so weak as compared with the frictional connection iei in that when the pin iii engages one of the sixty equally spaced teeth 53a on the wheel 53 the seconds hand 53 is slipped on the shaft Bl whereas the minute hand 52 maintains its position on shaft :33. The length of the pin 5i is preferably such that during operation of the gear train it can enter between two adjacent teeth on the wheel 53 but cannot pass the one tooth if such one tooth is in radial alignment of a line connecting shafts 3i and 63. Since there are 60 teeth on wheel 553 and shaft 3'5 rotates at 60% revolutions per hour, the seconds hand gains ,4; of 6 (degrees) or i /2 (degrees) during each revolution with respect to each tooth passage of wheel by the radial line connecting shafts and above mentioned. even though the pin 5! may under certain conditions pass the wheel edge of wheel without engaging one of the teeth on such wheel 53, this by its ability to gain 4 /2" during each toot passage (tooth on wheel 53 passing radial line) this pin 5i will eventually catch up to an extent to engage a tooth 53a on wheel By such engagement of a tooth 53a by the pin 58, the pin 5i will be very temporarily braked into minute synchronism, as it will be thereafter on each '1 revolution, and the pin 5i will engage successive teeth 53a on successive revolutions.

A portion of Fig. 1 has been shown on a larger scale in Fig. 2 of the drawings.

Since the seconds hand 5E3 rotates during about 99 percent of its revolution faster than does the seconds hand of an ordinary watch or clock it would at first hand appear that the seconds hand could not be used to time a race, for instance, and indicate accurate time. lhis is however not the case since it is proposed in accordance with this invention that the radial lines (not shown) defining seconds be placed 6.075 (degrees) apart for the first 59 seconds on the seconds hand dial. Then since 5Q 6.(l75:358.425 there will only be l..5'l5 left for the last or 60th second of the minute. ft is thus seen that the seconds hand and its hub must be slipped on shaft 2 to. an extent of 6.0'"Z5l.575 or during each th secon position of the seconds hand dial during the synchronization operation. Obviously the particular gear ratios and extent of fastness of shaft f ll above correct lapse of time is not limited to the ones chosen above. Also, instead of havthe shaft 3i rotate faster than 60 R. P. H. it may rotate less than 60 R. P. in which case the seconds hand will be advanced slightly in stead of being braked slightly by a tooth 53a on wheel or the shaft ti may be rotated exactly sixty times as fast as shaft 33 as shown in Fig. 4.

Qpcmtion.Let us assume that dimensions and juxtapositioning of the wheel 53 and its teeth to that of shaft 3i and pin 5i and also the radial lengths of the teeth 53a and pin M is such that at a particular revolution of shaft 3? the It is thus seen that pin 5! just missed a departing tooth 53a and was tooth pitch of teeth 53a ahead of the next tooth 53a in the rear when it entered between the two teeth 5301,. Under these dimensions and relationships of the structure the longest time it will ever take to re-synchronize the seconds hand after the minute hand has been reset will be 28 minutes. That is, for nineteen revolutions of pin 5! it will not touch a tooth 53a. This is due to the fact that the shaft 3? must gain to an extent of tooth pitch of teeth 53a or 1 /2 rotation of shaft is (with respect to shaft 3'5) When shaft it rotates 1 /2 the shaft 31 rotates 91.125". Also, shaft 3'! gains l in each revolution Since this seconds hand runs seconds fast per revolution, is is, to be more exact, only X 20.25=20 minutes It is thus seen that if the minute hand is set to an even minute when the seconds hand assumes any position between the i0 and 60 seconds position it will not take in excess of 20 minutes before synchronizing will take place. If on the other hand the seconds hand assumes any position between the zero and 39 seconds position the pin will on its first revolution strike a tooth to cause immediate minute synchronisation. The endof the pin 5'4 and the ends of the teeth should be rather sharp and so shaped that jamming therebetween is impossible.

Instead of employing the frictional connection 35G illustrated, which is mechanical, an eddy current disk and small permanent magnet to provide the usual eddy current drag may be used to constitute a slip clutch for the seconds hand. By the latter construction very little energy will be required during a clutch slipping operation. This is extremely important in small watches so as not to impair the time-keeping quality of such watch. In electric clocks of the synchronous motor type this is not so important in that sufficient energy is available. Such an eddy current slip clutch has been illustrated in Fig. 3 where plates '50-, H and T2 are parts of the clock frame, Sla is the seconds hand drive shaft (69.75 R. P. M.), 7-3 is the shaft to which the seconds hand 58a is connected (60 R. P. M), PM is a permanent magnet, 14 is the eddy current disk and 5 la is the synchronizing pin.

If. in a modified form of the invention, the shaft 3? is caused to run slower than normal, instead of faster than normal, as shown, the 60th second. on the seconds hand dial will be greater than 6 and each of the seconds markings to 59 inclusive will be less than 6 and in this case the seconds hand will be advanced instead of braked by a tooth 53a. It should be understood that the invention may, with or without modification, be applied to escapement clocks and watches.

It should be understood that the particular embodiment of the invention illustrated and described is exemplary and other embodiments not specifically illustrated but within the scope of the present invention may be employed. For instance, when the invention is applied to an escapement clock the direction of drive is from a slow running toward a fast running shaft whereas in. the form shown it is. vice versa. In an escapement clock you have continuous pressure between gear teeth and pinion teeth and there is no lost motion. In a synchronous motor electric clock it may be desirable to add a friction brake exerting a very small load on the i R. P. H. shaft so as to maintain tooth pressure and avoid lost motion. It will be observed that in the Fig. 1 construction the seconds hand runs counter-clockwise. This is not particularly harmful. If desired, however, an idling gear may be driven by the hub 38 and the second hand may be driven by such idling gear in which event the seconds hand will run clockwise.

Also, if desired, the shafts 31 and 43 may be operatively connected at a gear ratio of sixty to one. If this modified construction is used (see Fig. 4) the teeth 53w and pin 5| must be very accurately built and so designed that if pin 5| just passes a tooth 53a upon entering it cannot pass out without just wiping the next tooth 53b in advance thereof. By this construction minute synchronization is accomplished by braking action the same as in the preferred construction. In this Fig. 4 construction a uniformly divided seconds hand dial is used. In all other respects these two forms of the invention are identical. That is, the, seconds hand hub 38 and its associated pin 5| and shaft 31 rotate exactly sixty times as fast as shaft 43 and toothed wheel 53 in the modified construction shown in Fig. 4. In this construction the path of the end of pin 5| shown by dotted line 5 l overlaps the path of the ends of teeth 53a as shown by dotted line 530 to an extent that two teeth 53a fall within these overlapped arcs (see Fig. 4). It will be seen from Fig. 4 that if pin just misses tooth 53a it will strike the next tooth 53b, assuming for discussion only that toothed wheel 53 is not rotating. Since this wheel 53 is however rotating, the tooth 53?) will have moved to the dotted position 53b in the time required for the pin 5| to move from the entering point to the exit point of the overlap of dotted circles 5 c and 530 so that the pin 5| just misses the leaving tooth 53b (see its dotted position 53b) if it just missed the tooth 53a in the rear thereof. From this consideration it is readily seen that no matter what the chronological relationship between teeth 53a and pin 5| is after setting of the minute hand 52, the pin 5| and its associated seconds hand 50 will be set within the first minute after the minute hand was set. In view of the accuracy of construction required in the Fig. 4 form of the invention to obtain accurate time keeping by the second hand it is believed that the construction shown in Figs. 1 and 2 is preferably used. This is, however, a matter of choice.

In either the Fig. l or the Fig. 4 construction both the pin 5| and the teeth 53a are preferably very sharp with their sharp edges parallel to their axis of rotation so that end-to-end collision between such teeth and pin is improbable.

Having thus shown and described several embodiments of the present invention it should be understood that these embodiments are merely exemplary of structures coming within the scope of the invention and it should be understood that other structures may be used, and it should further be understood that various changes, modifications and additions may be made in practicing the invention without departing from this invention so long as these changes do not depart from the spirit or scope of the invention as defined by the following claims.

What I claim as new is:

1. In combination, a first time indicating shaft. first time indicating means frictionally connected to said first time shaft so that said first time indicating means may be set, a second time indicating shaft rotated in accordance with rotation of said first time indicating shaft but at a much higher speed, a second time indicating means frictionally connected to said second time indicating shaft for indicating fractional time increments of the time elements indicated by said first time indicating means, and wholly mechanical means supported wholly by said first time indicating means and at times directly engaging said second time indicating means to thereby set said second time indicating means so as to cause said second time indicating means to indicate definite equal fractional increments of and in addition to the time elements indicated by said first time indicating means.

2. Time indicating apparatus comprising, a minute shaft rotated at one revolution per hour, a minute manifesting means frictionally connected to said minute shaft, a gear train, a seconds manifesting shaft connected to said minute shaft by said gear train to cause said seconds manifesting shaft to be rotated at a speed different than one revolution per minute whereby said seconds manifesting shaft assumes a different position at the end of each minute manifested by said minute manifesting means, seconds manifesting means frictionally connected to said seconds manifesting shaft, and means for setting said seconds manifesting means by said minute manifesting means into minute synchronism when said seconds manifesting means and said minute manifesting means are within a predetermined extent of being in minute synchronism, whereby if said minute manifesting means is manually set to a different position on said minute shaft said seconds manifesting means if it is not already Within such predetermined extent of being in minute synchronism it will be later brought within such extent of minutes synchronism and will thereafter be set to minute synchronism with said minute manifesting means by said minute manifesting means.

3. Time indicating means comprising, a first time shaft, a first time indicating means frictionally connected to said first time shaft, a dial for said first time indicating means calibrated to provide equally spaced indicating points to indicate the total number of fractional elements of the time period indicated by one revolution of said first time shaft, a gear train, a second time shaft connected to said first time shaft by said gear train which has a gear ratio to cause said second time shaft to be rotated at a different speed than one revolution for one time element indicated by the first time indicating means on said dial, a second time indicating means frictionally connected to said second time shaft, a dial for said second time indicating means calibrated to indicate equal fractional increments of the time elements indicated by said first time indicating means on its associated dial so that by reason of the speed of rotation of said second time shaft with respect to said first shaft the total number of time increments traversed in one revolution of said second time shaft is different than a single time increments indicated by said first time indicating means, and setting means controlled by said first time indicating means to at times cause said second time indicating means to start a new revolution when said first time indicating means points at an indicating point on the dial of said first time indicating means by slipping said second time indicating means on said second time shaft.

4. Time indicating apparatus comprising, a minute shaft rotated at one revolution per hour,

a minute manifesting means frictionally connected to said minute shaft, a seconds manifesting, shaft. rotated at a speed different than one revolution per minute whereby said seconds manifesting shaft assumes a different position at the end of each minute indicated by said. minute manifesting means, seconds manifesting means connected to said seconds manifesting shaft through the medium of an eddy current drag, and means governed by said minute mam-- festing means for setting said seconds manifesting means on its shaft into minute synchronism when saidseconds manifesting means and said minute manifesting means are within a predetermined extent of being in minute synchro-- ni-sm, whereby if said minute manifesting means is manual-1y set toa different position on its shaft said seconds manifesting means is later set intominute synchronism with and by said minute manifesting means.

5. Time indicating apparatus comprising, a minute shaft rotated at one revolution per hour, a gear train, a minute manifesting means frictionally connected to said minute shaft, a seconds manifesting shaft gear connected to said. minute shaft by said gear train at a gear ratio so as to be rotated at a speed different than one revolution per minute whereby said seconds manifesting shaft assumes a different position at the end of each minute indicated 3y said min ute manifesting means, seconds manifesting means frictionally connected to said seconds manifesting shaft, and means wholly supported by said minute manifesting means for setting said seconds manifesting means on its shaft into minute synchronism when said seconds manifesting means and said minute manifesting means are within a predetermined extent of being in minute synchronism, whereby if said minute manifesting means is manually set to a different position on its shaft said seconds manifesting means is later set into minute synchronism by said minute manifesting means.

6. Time indicating apparatus comprising, a minute shaft rotated at one revolution per hour, a minute manifesting means frictionally connected to said minute shaft, a seconds manifest- Ling shaft rotated at a speed different than one revolution per minute whereby said seconds manifesting shaft assumes a different position the end of each minute indicated by said minute manifesting means, seconds manifesting means frictionally connected to said seconds manifesting shaft, a sixty toothed wheel connected to said. minute manifesting means and a single tooth means connected to said seconds manifesting means in such manner that said single tooth is at times in mesh with a tooth of said toothed wheel as a result of which said seconds manifesting means is forced into minute synchronism with said minute manifesting means when said seconds manifesting means comes within a predetermined extent of minute synchronism.

7. In combination, a first time indicating shaft, a first time indicating means frictionally connected to said time indicating shaft so that said time indicating means may be set, a second time indicating shaft, a second time indicating means for indicating fractional time increments of the time elements that are indicated by said first time indicating means and frictionally connected to said second time indicating shaft so that said second time indicating means may be set, and means including intermittently meshed gearing for causing said first time indicating means to at times set said second time indicating means, the second time indicating shaft operating at a different speed than one revolution in one time element as a result of which said second time indicating means assumes a different position at the end of, each time element until intermittent setting operation starts taking place.

8. In combination, a minute shaft operating :at a speed of one revolution per hour, a minute hand connected frictionally to said minute shaft, a second-hand shaft operating at a higher speed than one revolution. per minute, a seconds hand frictionally connected to. said second-hand shaft, whereby said second-hand shaft assumes a different position at the end of each minute manifested by said minute hand, and intermittently meshed gearing at times coupling said minute hand and said seconds hand for temporarily braking said seconds hand by said minute hand, such intermittent braking starting as soon as said seconds hand gets within approximate minute synchronism with said minute hand.

9. In combination, a minute shaft operating at a speed of one revolution per hour, a minute hand connected frictionally to said minute shaft, a seconds shaft operating at a different speed than one revolution per minute, a seconds hand frictionally connected to said seconds shaft whereby said seconds shaft assumes a different position at the end of each minute manifested by said minute hand so long as no setting operation takes place, and intermittently meshed gearing at times coupling said minute hand and said seconds hand for intermittently setting said seconds. hand by said minute hand, such intermittent setting starting when said seconds hand gets within approximate minute synchronism with said minute hand.

10. Time indicating apparatus comprising, a minute shaft rotating at one revolution per hour, a seconds shaft gear connected to said minute shaft so as to rotatev sixty and three-fourths revolutions for each revolution of said minute shaft, a wheel having sixty teeth and a minute hand frictionally connected to said minute shaft so that said minute hand may be set, means having a single tooth which may get into meshed relation with a tooth of said wheel and having a seconds hand associated therewith and frictionally connected to said seconds shaft, whereby if said minute hand is set said seconds hand is eventually intermittently braked into minute synchronism with said minute hand.

11. Time indicating apparatus comprising, a minute shaft rotated at a speed of one revolution per hour, a minute hand frictionally secured to said minute shaft, a gear train, a second shaft gear connected to said minute shaft by said gear train having a gear ratio such as to cause saidseconds shaft to be rotated at a speed exactly a small percent different than one revolution per minute so that it assumes a different position at the end of each minute manifested by rotation of said minute hand with said minute shaft, a seconds hand frictionally secured to said seconds shaft, and means efiective to set said seconds hand into. chronological agreement with said minute hand at the end of each minute provided said seconds hand is then with in a predetermined extent of being in such chronological agreement, whereby if said minute hand is manually set said seconds hand will when it eventually gets within such predetermined extent of being in such chronological agreement will be automatically set into chronological agreement with said minute hand.

12. Time indicating apparatus comprising, a. minute shaft rotated at a speed of one revolution per hour, a gear train, a second-hand shaft gear connected by said gear train to said minute shaft, minute means including a minute hand frictionally secured to said minute shaft, a seconds hand frictionally secured to said second-hand shaft, and means Wholly supported by said minute means for setting said seconds hand into chronological agreement with said minute hand at the end of each minute whereby if said minute means is manually set said seconds hand will be automatically set so as to be in chronological agreement with said minute hand.

13. Time indicating apparatus comprising, a minute shaft rotated at a speed of one revolution per hour, a second-hand shaft gear connected to said minute shaft, a minute means frictionally secured to said minute shaft, a seconds hand frictionally secured to said second-hand shaft, and means controlled by said minute means for setting said seconds hand into chronological agreement with said minute means during the first minute following setting of the minute means, whereby if said minute mean is manually set said seconds hand will be automatically set so as to be in chronological agreement with said minute means.

14. Time indicating apparatus comprising, a minute shaft rotated at a speed of one revolution per hour, a second-hand shaft gear connected to said minute shaft, a minute hand frictional secured to said minute shaft by means including a frictional connection, a setting member fixedly connected to said minute hand and having a plurality of setting teeth located about its periphery at points spaced arcs of degrees divisible by six, a seconds hand frictionally secured to said secend-hand shaft by means including a frictional connection, a setting tooth fixedly connected to said second hand and located so as to be engageable by a setting tooth of said setting memher if said seconds hand is not indicating the Proper fraction of the minute indicated by said minute hand during operation of said time indicating apparatus, said frictional connections imposing frictions respectively such that the minute hand dominates said seconds hand, whereby if said minute hand is set manually said seconds hand will be set automatically.

15. Time indicating apparatus comprising, a minute indicating shaft rotated at a speed of one revolution per hour, a seconds indicating shaft gear connected to said minute indicating shaft to rotate at a higher speed, a minute hand frictionally secured to said minute indicating shaft by means including a frictional connection, a seconds hand fricti'onally connected to said seconds indicating shaft by means including a frictional connection, said frictional connections imposing frictions respectively such that the frictional connection driving said minute hand imposes a much greater friction than does the frictional connection driving said seconds hand, and interengaging means supported wholly by said minute hand and said seconds hand for causing said minute hand to set said seconds hand into chronological agreement with said minute hand, whereby if said minute hand is set manually said seconds hand is set by said minute hand automatically.

OSCAR H. DICKE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,933,923 Neureuther Nov. 7, 1933 2,359,458 Amend, Jr., et a1 Oct. 4, 1944 

